glassy

Concise Oxford English Dictionary © 2008 Oxford University Press:
glassy/ˈɡlɑːsi/

▶adjective (glassier, glassiest)

• 1 of or resembling glass.

  ■ (of water) having a smooth surface.

• 2 (of a person's eyes or expression) showing no interest or animation.

– derivatives
glassily adverb,
glassiness noun.